[Rd] Redhat 7.2 gcc optimisation (PR#4459)

[p.murrell at auckland.ac.nz]

Hi

The the gcc on Redhat 7.2 with default C compiler configuration setting 
CFLAGS="-g -O2" produces some worrying differences in output compared to 
CFLAGS="-g -Wall -pedantic"

The following differences were seen in graphical output from running 
examples:

besselI
     DIFFERENCE in example 4
     DIFFERENCE in example 5
(1e+00 becomes 1e-00 in axis label)
--
co.intervals
     DIFFERENCE in example 8
(third y-value in lowess curve different)!!!
--
dnbinom
     DIFFERENCE in example 2
(contour line labels at different locations)
--
pbirthday
     DIFFERENCE in example 1
(1e+00 becomes 1e-00 in axis label)
--
persp
     DIFFERENCE in example 3
(order of drawing surface facets different)


####### Reproduction details

Differences were detected in graphics output using the graphicsQC 
package (see http://www.stat.auckland.ac.nz/~paul/index.html) and ...

model.graphics(package="base", device="postscript", format="pbm",
                model.loc="model", verbose=TRUE)

... to produce output for CFLAGS="-g -O2" and ...

test.graphics(package="base", device="postscript", format="pbm",
               model.loc="model", test.loc="test", verbose=TRUE)

... to produce output for CFLAGS="-g -Wall -pedantic"

Paul

--please do not edit the information below--

Version:
  platform = i686-pc-linux-gnu
  arch = i686
  os = linux-gnu
  system = i686, linux-gnu
  status = beta
  major = 1
  minor = 8.0
  year = 2003
  month = 10
  day = 07
  language = R

Search Path:
  .GlobalEnv, package:methods, package:ctest, package:mva, 
package:modreg, package:nls, package:ts, package:lattice, package:grid, 
package:graphicsQC, Autoloads, package:base

-- 
Dr Paul Murrell
Department of Statistics
The University of Auckland
Private Bag 92019
Auckland
New Zealand
64 9 3737599 x85392
paul at stat.auckland.ac.nz
http://www.stat.auckland.ac.nz/~paul/